摘要
为了建立Iodogen直接法碘标记反义寡核苷酸(ASON)方法,评价探针的稳定性及生物分布特征。用Iodogen对15merbcl-2mRNA的反义寡核苷酸进行直接标记,SephadexG-25凝胶柱纯化,测定标记率和纯度,评价标记ASON的稳定性。在BALB/c裸鼠及荷CNE2瘤小鼠中研究其生物分布特征。结果显示:1)在适当条件下,本法标记率可达85%,放射性纯度为90%,放射性比度为4.77×105Bq/μg(ASON)。2)标记ASON室温下96h保持较稳定,但新鲜血浆下部分分解。3)标记ASON在大多数组织器官中的放射性活度随时间减少迅速,大多数曲线呈示踪剂为两相分布。30min时胃肠道和甲状腺放射性浓集明显,提示标记探针体内不稳定。肿瘤对探针的摄取较少,免疫组化证实肿瘤组织bcl-2表达极低。结果表明Iodogen直接法碘标记反义寡核苷酸(ASON)方法简单可靠,可获得标记率高、纯度较高且稳定性较好的标记探针,但碘标寡核苷酸在体内因核酶的分解而稳定性较差。
To establish a method for directly labeling antisense oligonucleotide ( ASON ) with iodine and evaluate the stability and biodistribution of labeled ASON, 15mer bcl-2 ASON to mRNA was labeled with iodine by Iodogen, purified with Sephadex G-25. Labelling efficiency and purity of labeled ASON were measured, and the stability was evaluated. Biodistribution of labeled ASON was studied in BALB/c nude mice and CNE2 bearing mice. Results showed that 1) The Labelling efficiency was 85% under suitable conditions and radiopurity was 90%, and specific radioactivity was 4.77 × 105Bq/ μ g ( ASON ) . 2) The labeled ASON was stable at room temperature, but disintegrated partly in fresh serum. 3) The radioactivity of labeled ASON decreased fast in most of organs, presenting a two-phase distribution. The uptakes of radioactivity in thyroid gland and gastrointestine were obvious, indicating labeled ASON were not stable. Tumor tissues had little ASON uptake, and immunohistological test confirmed that the expression of bcl-2 in CNE2 was very low. These findings indicated that directly iodine labeling ASON with Iodogen was simple and reliable, and it could provide high labelling efficiency, high specific activity and stable labeled ASON. But stability of labeled ASON was poor in vivo due to disintegration of nucleotidase.
出处
《核技术》
CAS
CSCD
北大核心
2004年第5期365-369,共5页
Nuclear Techniques